Differences in mortality in a cohort of cocaine use disorder patients with concurrent alcohol or opiates disorder

Explaining the high mortality among opioid-cocaine co-users compared to opioid-only users. A systematic review

RATIONALE

The opioid crisis in North America has recently seen a fourth wave, which is dominated by drug-related deaths due to the combined use of illicitly manufactured fentanyl [IMF] and stimulants such as cocaine and methamphetamine.

OBJECTIVES

A systematic review addressing the question why drug users combine opioids and stimulants and why the combination results in such a high overdose mortality: from specific and dangerous pharmacokinetic or pharmacodynamic interactions or from accidental poisoning?

RESULTS

Motives for the combined use include a more intensive high or rush when used at the same time, and some users have the unfounded and dangerous belief that co-use of stimulants will counteract opioid-induced respiratory depression. Overdose deaths due to combined (intravenous) use of opioids and stimulants are not likely to be caused by specific pharmacokinetic or pharmacodynamic interactions between the two drugs and it is unlikely that the main cause of overdose deaths is due to accidental poisoning.

CONCLUSION

The unexpectedly high overdose rates in this population could not be attributed to accidental overdosing or pharmacokinetic/pharmacodynamic interactions. The most likely explanation for the high rate of drug-related deaths in opioid-cocaine co-users is careless overdosing with either cocaine, opioid(s) or both, probably facilitated by the high level of preexisting impulsivity in these co-users and a further acute increase in impulsivity following cocaine use. The primary corollary is that cocaine users should avoid IMF use in the same time window. In addition, IMF users should refrain from cocaine use to avoid impulsive IMF overdosing.

Factors associated with suicide in people who use drugs: a scoping review

BACKGROUND

Suicide is a significant contributor to global mortality. People who use drugs (PWUD) are at increased risk of death by suicide relative to the general population, but there is a lack of information on associated candidate factors for suicide in this group. The aim of this study was to provide a comprehensive overview of existing evidence on potential factors for death by suicide in PWUD.

METHODS

A scoping review was conducted according to the Arksey and O'Malley framework. Articles were identified using Medline, CINAHL, PsycINFO, SOCIndex, the Cochrane Database of Systematic Reviews and the Campbell Collaboration Database of Systematic Reviews; supplemented by grey literature, technical reports, and consultation with experts. No limitations were placed on study design. Publications in English from January 2000 to December 2021 were included. Two reviewers independently screened full-text publications for inclusion. Extracted data were collated using tables and accompanying narrative descriptive summaries. The review was reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) guidelines.

RESULTS

The initial search identified 12,389 individual publications, of which 53 met the inclusion criteria. The majority (87%) of included publications were primary research, with an uncontrolled, retrospective study design. The most common data sources were drug treatment databases or national death indexes. Eleven potential factors associated with death by suicide among PWUD were identified: sex; mental health conditions; periods of heightened vulnerability; age profile; use of stimulants, cannabis, or new psychoactive substances; specific medical conditions; lack of dual diagnosis service provision; homelessness; incarceration; intravenous drug use; and race or ethnicity. Opioids, followed by cannabis and stimulant drugs were the most prevalent drugs of use in PWUD who died by suicide. A large proportion of evidence was related to opioid use; therefore, more primary research on suicide and explicit risk factors is required.

CONCLUSIONS

The majority of studies exploring factors associated with death by suicide among PWUD involved descriptive epidemiological data, with limited in-depth analyses of explicit risk factors. To prevent suicide in PWUD, it is important to consider potential risk factors and type of drug use, and to tailor policies and practices accordingly.

All-cause and cause-specific mortality among people with regular or problematic cocaine use: a systematic review and meta-analysis

AIMS

To estimate pooled all-cause and cause-specific mortality risk for people with regular or problematic cocaine use.

METHODS

Systematic review and meta-analysis of prospective or retrospective cohort studies or clinical trials (n ≥30) of people with regular or problematic cocaine use with data on all-cause or cause-specific mortality. Of 2808 papers, 28 were eligible and reported on 21 cohorts, with a total 170 019 individuals. Cohorts identified based on acute care for drug poisoning or other severe health presentation were excluded. Title/abstract screening was conducted by one reviewer; a second reviewer independently checked 10% of excluded studies. Two reviewers conducted full-text screening. Data were extracted by one reviewer and checked by a second. A customized review-specific study reporting quality/risk of bias tool was used. Data on crude mortality rates (CMR) and standardized mortality ratios were extracted for both all-cause and cause-specific mortality. Standardized mortality ratios were imputed where not provided by the author using extracted data and information from the Global Burden of Disease Study 2017. Data were pooled using a random-effects model.

RESULTS

The pooled all-cause crude mortality rate was 1.24 per 100 person-years [95% confidence interval (CI) = 0.86, 1.78; n = 16 cohorts], but with considerable heterogeneity (I²  = 98.8%). The pooled all-cause standardized mortality ratio (SMR) was 6.13 (95% CI = 4.15, 9.05; n = 16 cohorts). Suicide (SMR = 6.26, 95% CI = 2.84, 13.80), accidental injury (SMR = 6.36, 95% CI = 4.18, 9.68), homicide (SMR = 9.38, 95% CI 3.45-25.48) and AIDS-related mortality (SMR = 23.12, 95% CI = 11.30, 47.31) were all elevated compared with age and sex peers in the general population.

CONCLUSIONS

There are elevated rates of mortality among people with regular or problematic cocaine use for traumatic deaths and deaths attributable to infectious disease.